Debugging em(4) driver

[Patrick Mahan]

On 11/13/2010 09:08 PM, Jack Vogel wrote:
> The stats changed quite a bit for 8.1, they are much more informative now,
> and they can be collected from anywhere not just the console.
>
> I don't quite understand what you are trying to do, debug an em problem
> or just debug a problematic situation by using em??
>
> Mike is right, the driver in HEAD has some significant fixes and would be
> the best thing to use.
>

We were noticing a lot of slow down on the link between the two HPs.  I would
start a normal ping between the two boxes, start the traffic generation and
I would see the ping's completely stop, even though I could see I was still
getting traffic on the em(4) interface.  Once the pings stop, we eventually
started seeing failure in our network app that needs to query it's peer.  It
would timeout trying to send a notification message to it's peer.

I wanted to see if there was a failure somewhere in the interface layer such
as dropping packets.  Plus I wanted to ensure the ringbuffer em(4) was using
wasn't starving for packets.

Patrick